One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6)(7,8)(9,10,15,13)(11,16,14,21)(12,17,19,22)(18,23,20,24)(2,6)(4,7)(9,11,15,14)(10,16,13,21)(12,18,19,20)(17,23,22,24)(25,26,30,31)(27,32,35,40)(28,33,38,37)(29,34,39,36)(1,2,5,6)(3,7,8,4)(10,13)(11,14)(12,19)(23,24)(26,31)(27,35)(28,38)(29,39)(1,3)(2,7)(4,6)(5,8)(9,12)(10,17)(11,18)(13,22)(14,20)(15,19)(16,23)(21,24)(25,27)(26,32)(28,34)(29,37)(30,35)(31,40)(33,39)(36,38) involution — undirected(1,4,5,7)(2,3,6,8)(9,13,15,10)(11,16,14,21)(12,17,19,22)(18,24,20,23)(25,28)(26,33)(27,36)(29,32)(30,38)(31,37)(34,35)(39,40)(1,3)(2,7)(4,6)(5,8)(9,14,15,11)(10,16,13,21)(12,20,19,18)(17,23,22,24)(25,29)(26,34)(27,37)(28,32)(30,39)(31,36)(33,35)(38,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.